The Field Season Begins!

Monday (3/24/14) was the first day of my field work!

I've teamed up with Jenny Phillips from Tulane University to begin color banding San Francisco Nuttall's white-crowned sparrows. Jenny's working on a song-related project as well but hers involves studying the effects of anthropogenic (human-derived) noise on NWCS song production and transmission.

We started at Lake Merced - right next to San Francisco State University. 

We were target netting with male songs that Jenny had recorded previously. Responses were strong but the birds didn't always fly into the nets. Sometimes they perched frustratingly close and just sung back in response. However, we did catch a few individuals. 

Jenny (right) and her field assistant Kathleen setting up a net. 

A local conservation organization, Point Blue Conservation Science, generated color band codes for us to affix to the white-crowns. The codes are read from left leg to right leg and from body to foot. So this bird would get a color code of S/YOB (silver for the USGS band on his left leg, then Yellow, Orange, Blue for the three on his right):

That way when we go back to Lake Merced for follow up research we know we are working with individual "S/YOB"

After banding we took some standard measurements such as age, weight, feather wear, and bill measurements. These last measurements are especially important because the shape and size of a bill can affect a song - much like how our mouths affect how different sounds are produced in human language. We also took blood samples for my parasite study. 

Kathleen with one of the Lake Merced Nuttall's white-crowned sparrows.

Turns out there's other wildlife at Lake Merced as well:

Coyote Creek Banding Station

Before beginning graduate school in August 2013, I hadn't had much experience handling birds. I took an ornithology class as an undergraduate where I got some exposure to mist nets and saw a few birds up close but hadn't actually handled any.

I had to build up this experience pretty quickly as it's required when applying for permits. Luckily, my lab mate, Allison, introduced me to the San Francisco Bay Bird Observatory and their banding station at Coyote Creek. The banding station is run by Josh Scullen, a certified master bander by the USGS (a huge deal - according to the USGS there are only 2,000 master banders in the US.)

Other than Josh, the station is entirely volunteer run. Each Wednesday, Saturday, and Sunday 3-6 volunteers show up at dawn and work for 5 hours, conducting net runs every 30 minutes. Net runs involve walking the length of the 15 or so nets and extracting (taking out of the net) any birds that are caught. Birds then go back to the banding trailer where they await their turn to be processed (measured, weighed, aged, etc.)

The clips designate which net the bird was caught in. Bags get a red clip if the bird is small or a species that tends to stress easily, such as a warbler or flycatcher.

This is Jazzy, excited in the early morning hours to be processing a pacific-slope flycatcher.

It is here that I've been able to get weekly practice extracting birds from nets, handling them, and taking the necessary measurements. The station is in Milpitas, north of San Jose and about a 45 minute drive from my house.

I usually go down on Sundays and since I went today I took a bunch of bird photos with this blog in mind. You can click on each species name to read more about them at Cornell's All About Birds website.

Yellow-rumped Warbler

Golden-crowned Sparrow

These are in the same genus (Zonotrichia) as the white-crowns.

California Towhee 

A big bird, relatively.

Hermit Thrush

This is the species Allison studies.

White-crowned Sparrow (PSWS)

You know this one! (Pugnacious, right?)

Ruby-crowned Kinglet

You might be wondering why this one is called "ruby-crowned":

Males have this hidden red crest.

Common Yellowthroat

Chestnut-backed Chickadee

These guys are known around the banding station as "tweezer beaks" because they are highly likely to bite you while you're trying to extract them. It feels like getting pinched by tweezers.

The namesake of this chickadee species.

Hope you enjoyed the birds! I do.

Meet the White-crowned Sparrow

Now it's time to meet the star of the show: the Nuttall's white-crowned sparrow (scientific name: Zonotrichia leucophrys nuttalli)

Photo by K. Schneider on Flickr

White-crowned sparrows are quite common and found all over the United States. However, even though they are all the same species, they are divided up into five different subspecies, determined mostly by migration patterns. The three we get here in San Francisco are Puget Sound (known affectionately by their four letter banding code as PSWS or "piss wiss"), Gambel's (GWCS) and Nuttall's white-crowned sparrow (NWCS).

Of the five subspecies, NWCS, is the only one that is non-migratory. Since they don't move very far from where they were hatched, it is easier to determine where they picked up a parasite.

The songs of white-crowned sparrows have also been extensively studied. Unlike birds with repertoires like mockingbirds, white-crowns sing a single song type. However, within that one song type there are many variations (Baptista 1977). When learning about birds and specifically bird song, white-crowned sparrows are always brought up as the classic example of song dialects. Dialects are like accents in human communication - they're "speaking the same language" just with different inflections. Juveniles learn to sing by listening to their fathers and male neighbors (DeWolf et al. 1989) and females preferentially mate with males singing the dialect they grew up hearing (Baker 1983). Thus the dialects are reenforced.

Even within the same subspecies there are populations that sing different dialects. Here's a map of San Francisco showing three different Nuttall's dialects recorded in 1975:

Luther, D., and L. Baptista (2010) Urban noise and the cultural evolution of bird songs. Proceedings of the Royal Society B: Biological Sciences, 277(1680): 469-473

The diagrams on the left are spectrograms, a visual representation of a song that graphs frequency over time.

To match the audio with the visual, this is a bird I recorded sining in Cesar Chavez Park. He was in this bush:

And here is the associated spectrogram:

And now you've met the white-crowned sparrows! You will see (and hear) many more in the posts to come. 

For some reason the word that comes to mind when I see a male white-crown is pugnacious. They kind of look angry and determined all the time. 

Photo by Anders Illum on Flickr

Background - Bird Song

Part II in filling in the background of my project: Bird Song!

Bird Song

If you've ever tried bird watching before you know that you often hear a bird before you see it. Over half of all bird species are in the order Passeriformes, more commonly known as passerines, and even more commonly known as songbirds. 

If you hear a bird singing, it is most likely a male. Males sing both to attract mates and to defend their territories. Song is what is called a sexually-selected trait. Unlike natural selection where traits evolve to help a species survive, sexually-selected traits help individuals (usually the males) acquire mates. The classic example is the peacock's tail. It serves no function in keeping the male alive, but the ladies love it.

Photo by John Benson on Flickr

The same with bird song. Female birds are able to analyze a male's song to determine if he is a good candidate for a mate. If a bird is infected with a parasite and his song is affected, a female may choose not to pair up with him.

Song is a complicated trait and can be altered by many different factors. It can be difficult to isolate the effects of any one influence. To narrow the focus, I will be looking into performance-related aspects of song. These relate to energy demands and include things like:

• song rate - how fast is the bird singing?
• song amplitude - how loud is the bird singing?
• song consistency - how consistent is the bird from song to song?
• etc.

In general, previous studies I've found have shown that performance-related aspects are negatively affected by parasites (slower song rate, lower amplitude, inconsistency between songs) and I predict that white-crowned sparrows infected with avian malaria will show similar patterns.



The Cornell Lab of Ornithology is one of the best resources for all things "bird." Here's a great page from the Lab with different clips of some common North American birds: Songs & Calls